Field of the Invention
The invention relates to an image processing apparatus, and more particularly, to artifact reduction method and apparatus and image processing method and apparatus.
Description of Related Art
Composite video systems (e.g., NTSC or PAL) transmit color information through color sub-carriers superimposed on luminance signals. Generally, luminance signals and chrominance signal share frequency bands commonly in practical uses. As a result, two types of artifacts (e.g., cross-chroma and cross-luma) are usually found in composite videos.
When a frequency component of the luminance signal is close to a frequency of the color sub-carrier, a cross-chroma may occur to cause generation of color noise in frames. The cross-chroma may sometimes be referred to as bleeding or rainbow effects. Cross-luma occurs nearby edges with highly saturated color, and acts like a series of crawling dots (or also known as dot crawls). Cross-luma often results in color information being confused with brightness information. For viewers, artifacts like cross-luma in stationary areas are quite obvious and annoying.